1. Field of the Invention
The present invention relates to a microwave plasma generator, and particular to a microwave plasma generator which can be easily operated to generate clean and uniform plasma and applied to semiconductor manufacturing processes, for example, material modification, etching/cleaning, roughing and ion doping/hybrid.
2. Related prior Arts
Currently, plasma is applied in high technologies, for example, photoelectric devices and semiconductor manufacturing. The traditional plasma sources include the capacitive plasma source, the microwave plasma source, the inductive coupling plasma source, the electron cyclotron resonance plasma source, etc.
Among the above plasma sources, the microwave plasma source utilizes radio frequency electromagnetic waves to heat electrons and supply energy thereto. Features of the microwave plasma source can generate clean and high density plasma but not uniform. Therefore, the reactive chamber is limited in dimension. The electron cyclotron resonance plasma source utilizes electrons cycling in a magnetic field with a constant frequency and accelerating in a resonant frequency to generate uniform and high density plasma. However, the chamber of the electron cyclotron resonance plasma source is complicated. The inductive coupling plasma source utilizes a spiral coil as an electron source in a magnetic field to ionize a gas and generate plasma. The inductive coupling plasma source is easily achieved, but generally companioned with high temperature.
To comply with requirements in semiconductor manufacturing, it's necessary to develop a microwave plasma generator or source capable of generating stable and uniform plasma.